Molal Solubility, Dissociation, Association and Solvation Parameters for Saturated Phenylalanine Solutions in Various Solvents at 298.15 K

The molal solubilities for saturated solutions of phenylalanine at 298.15 K in various solvents were determined. The solvents used are, water (W), ethanol (Et), dimethylsulphoxide (DMSO), acetonitrile (AN), methanol (Me), acetone (Ac), 1-4, dioxane (Di) and N, N-dimethylformamide (DMF).From the experimental data for solubilities, pH and densities, the different volumes, molar: electrostriction and Van der Waals and apparent molar volumes were estimated. The free energies of dissociation (ΔGd), free energies of association (ΔGA), difference free energies (ΔΔG) and free energies of solvation (ΔGs) for phenylalanine saturated solutions in various solvents were also calculated. The solvation numbers were also estimated. It was concluded that the solute-solvent interaction increased by increasing the solvation free energies due mainly to the greater of the association parameters in the organic solvents.